Hi Laurent, On Fri, Apr 12, 2024 at 10:07:46PM +0300, Laurent Pinchart wrote: > Hi Sakari, > > On Thu, Apr 11, 2024 at 09:04:47AM +0000, Sakari Ailus wrote: > > On Thu, Mar 21, 2024 at 06:49:14PM +0200, Laurent Pinchart wrote: > > > On Wed, Mar 13, 2024 at 09:25:01AM +0200, Sakari Ailus wrote: > > > > Add new MIPI CCS embedded data media bus code > > > > (MEDIA_BUS_FMT_CCS_EMBEDDED). > > > > > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > > > --- > > > > .../media/v4l/subdev-formats.rst | 28 +++++++++++++++++++ > > > > include/uapi/linux/media-bus-format.h | 3 ++ > > > > 2 files changed, 31 insertions(+) > > > > > > > > diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst > > > > index cbd475f7cae9..c8f982411e70 100644 > > > > --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst > > > > +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst > > > > @@ -8564,3 +8564,31 @@ and finally the bit number in subscript. "X" indicates a padding bit. > > > > - X > > > > - X > > > > - X > > > > + > > > > +.. _MEDIA-BUS-FMT-CCS-EMBEDDED: > > > > + > > > > +MIPI CCS Embedded Data Formats > > > > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > > + > > > > +`MIPI CCS <https://www.mipi.org/specifications/camera-command-set>`_ defines a > > > > +metadata format for sensor embedded data, which is used to store the register > > > > +configuration used for capturing a given frame. The format is defined in the CCS > > > > +specification. The media bus code for this format is > > > > +``MEDIA_BUS_FMT_CCS_EMBEDDED``. > > > > + > > > > +The CCS embedded data format definition includes three levels: > > > > + > > > > +1. Padding within CSI-2 bus :ref:`Data unit <media-glossary-data-unit>` as > > > > > > s/Data unit/Data Unit/ > > > > Yes. > > > > > > + documented in the MIPI CCS specification. > > > > + > > > > +2. The tagged data format as documented in the MIPI CCS specification. > > > > + > > > > +3. Register addresses and register documentation as documented in the MIPI CCS > > > > + specification. > > > > + > > > > +The format definition shall be used only by devices that fulfill all three > > > > +levels above. > > > > > > Hmmmm... Do we need to mandate level 3 ? There are lots of sensors that > > > comply with the first two levels but have their own register set. Would > > > you like a sensor-specific embedded data format for each of them ? If > > > so, how would we document it without essentially copying the datasheet ? > > > > You could refer to the datasheet if it's publicly available. > > What if it's not ? How would you expect documentation to be organized ? > Will we then end up adding one media bus code per sensor ? Probably. The user space needs a way to find out what to expect. If a sensor produces its own custom metadata format, it needs to be documented. There's also documentation for OV2740 embedded data in the set. -- Sakari Ailus
